1. Field of the Invention
The present invention relates to a laser apparatus in which one or more laser beams emitted from one or more semiconductor lasers contained in a package are optically combined in an optical fiber. The present invention also relates to a method for assembling the above laser apparatus, and to a structure for installing the above laser apparatus in a system which uses the laser apparatus.
2. Description of the Related Art
Some known types of laser apparatuses optically combine a plurality of laser beams in a single optical fiber, and output a high-power laser beam by inputting the plurality of laser beams into the single optical fiber. For example, such laser apparatuses are disclosed in U.S. Pat. No. 6,995,912 and Japanese Unexamined Patent Publication No. 2004-045667. The disclosed laser apparatuses are basically constituted by one or more semiconductor lasers which emit a plurality of laser beams, a single optical fiber, and an optical condensing system which condenses the plurality of laser beams and couples the condensed laser beams to the optical fiber.
In addition, in another known type of laser apparatus, a laser beam emitted from a single semiconductor laser is condensed by an optical condensing system, and is then coupled to an optical fiber. For example, such a laser apparatus is disclosed in European Patent Publication No. 0631164.
In many of the above types of laser apparatuses, the optical condensing systems and the semiconductor lasers are hermetically sealed in a package for prevention of contamination. In the case where such a package is used, a light-entrance end of the optical fiber is held in the package in such a manner that the light-entrance end faces the optical condensing system. In a conventionally known structure for holding the optical fiber as above, the optical fiber is simply fixed to a sidewall or the like of the package with a brazing material or an adhesive, as disclosed in Japanese Unexamined Patent Publication No. 2004-045667. Further, European Patent Publication No. 0631164 discloses a technique wherein a mechanism for adjustment of the position of a ferrule holding the optical fiber is arranged in advance at a sidewall of the package, where the mechanism enables adjustment of the position of the ferrule in the direction of the core axis and the direction perpendicular to the core axis, so that the optical fiber can be set at an optimum position with respect to the optical condensing system by using the above mechanism before the ferrule is fixed to the package.
However, in the structure for holding the optical fiber disclosed in Japanese Unexamined Patent Publication No. 2004-045667, no further provision is made for optimumly positioning the optical condensing system with respect to the optical fiber fixed to the package. Therefore, the operation for aligning the optical fiber with the optical condensing system is not easy.
On the other hand, in the structure for holding the optical fiber disclosed in European Patent Publication No. 0631164, the operation for aligning the optical fiber with the optical condensing system is easy. However, in this structure, the aforementioned mechanism for adjusting the ferrule which holds the optical fiber is provided in advance at the sidewall of the package. Therefore, the overall size of the package becomes great.